I've carried a pocket knife since I was a kid. I think my granddad gave me my first - probably to mark the start of my very short-lived career in the Sea Scouts. Since then I should think that I have used my pocket knives pretty much every other day - for any task from eating at my desk to re-wiring my bikes at the side of the road.
Along with wearing a watch and carrying a wallet, I feel naked not to be carrying a pocket-knife. And I think this was a common attitude for generations - part of a more innocent and 'real' culture - before we gave up trying to fix stuff for ourselves or became obsessed with health and safety.
Stabbing anyone - in self-defense or otherwise - has never been on my agenda but the recent anti-knife hysteria has criminalized this habit and most of my collection of pocket knives is now illegal. Generally because the blades can be locked - although this is actually a safety feature to prevent you cutting your own fingers off.
I have even had two perfectly legal knives confiscated by the authorities - one a Swiss Army knife I happened to have on me at a carnival and another I tried to take on the EuroStar which they like to pretend is really an airplane - presumably they were afraid I might hi-jack it and divert the train to crash in to a public building. (On the first occasion I was given a receipt by the police so the knife could be returned but some copper must have taken a fancy to it because it had been mysteriously 'lost' when i tried to reclaim it).
So I find myself for once strangely in sympathy with the gun-lobby - 'it's not pen-knives that kill people it's angry teenagers'. And I've been on the look out for a nice pocket-knife that is also legal - essentially a folding blade that cannot be locked and has an edge of 3.5 inches or less.
Then I saw this article about Trevor Ablett who makes such knives - by hand in the same way as has been done in Sheffield for 150 years, and at the same price you can buy a mass-produced plastic item in the shops. Too good to resist.